diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index 81e5990d36..71c042f4e0 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -2669,9 +2669,18 @@ void ModelVolume::update_extruder_count_when_delete_filament(size_t extruder_cou
     // Same stale-assignment cleanup as update_extruder_count, for the filament-delete path.
     // Ported from BambuStudio (STUDIO-15763).
     size_t eid = extruder_id();
-    if (eid > extruder_count) {
-        // A mixed-color slot is virtual and legitimately sits past the physical filament count,
-        // so an assignment to one is not stale and must survive the delete.
+    // Judge out-of-range against the post-remap id, mirroring update_filament_values_for_items_when_delete_filament.
+    // Using the pre-remap eid would wrongly erase a high extruder that should remap (e.g. 5 -> 4 after
+    // deleting filament 1); update_filament_values_for_items_when_delete_filament would then skip it
+    // (!has("extruder")) and the volume would fall back to the object default color.
+    size_t remapped = eid;
+    if (eid == filament_id)
+        remapped = (replace_filament_id > 0) ? (size_t)replace_filament_id : 1;
+    else if (eid > filament_id)
+        remapped = eid - 1;
+    if (remapped > extruder_count) {
+        // filament_is_mixed is the pre-delete snapshot; index it with the ORIGINAL eid (1-based),
+        // not remapped, so we check whether this volume's current slot is a mixed slot.
         bool is_mixed = !filament_is_mixed.empty() && eid >= 1 && (eid - 1) < filament_is_mixed.size() && filament_is_mixed[eid - 1];
         if (!is_mixed)
             this->config.erase("extruder");
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 29e6dab244..4676ff3c4b 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -5294,43 +5294,44 @@ void Sidebar::on_filaments_delete(size_t filament_id)
 {
     auto &choices = combos_filament();
 
-    if (filament_id >= choices.size())
-        return;
+    // A mixed (virtual) slot has no combo of its own, so there is no combo UI to remove —
+    // but the shared refresh below must still run so the mixed filament panel drops its row.
+    if (filament_id < choices.size()) {
+        if (choices.size() == 1)
+            choices[0]->GetDropDown().Invalidate();
 
-    if (choices.size() == 1)
-        choices[0]->GetDropDown().Invalidate();
+        wxWindowUpdateLocker noUpdates_scrolled_panel(this);
 
-    wxWindowUpdateLocker noUpdates_scrolled_panel(this);
+        // delete UI item
+        {
+            const int last            = p->combos_filament.size() - 1;
+            auto      sizer_filaments = this->p->sizer_filaments->GetItem(last % 2)->GetSizer();
+            sizer_filaments->Remove(last / 2);
 
-    // delete UI item
-    if (filament_id < p->combos_filament.size()) {
-        const int last            = p->combos_filament.size() - 1;
-        auto      sizer_filaments = this->p->sizer_filaments->GetItem(last % 2)->GetSizer();
-        sizer_filaments->Remove(last / 2);
+            PlaterPresetComboBox* to_delete_combox = p->combos_filament[filament_id];
+            (*p->combos_filament[last]).Destroy();
+            p->combos_filament.pop_back();
 
-        PlaterPresetComboBox* to_delete_combox = p->combos_filament[filament_id];
-        (*p->combos_filament[last]).Destroy();
-        p->combos_filament.pop_back();
-
-        // BBS:  filament double columns
-        auto sizer_filaments0 = this->p->sizer_filaments->GetItem((size_t) 0)->GetSizer();
-        auto sizer_filaments1 = this->p->sizer_filaments->GetItem(1)->GetSizer();
-        if (p->combos_filament.size() < 2) {
-            sizer_filaments1->Clear();
-        } else {
-            size_t c0 = sizer_filaments0->GetChildren().GetCount();
-            size_t c1 = sizer_filaments1->GetChildren().GetCount();
-            if (c0 < c1)
-                sizer_filaments1->Remove(c1 - 1);
-            else if (c0 > c1)
-                sizer_filaments1->AddStretchSpacer(1);
+            // BBS:  filament double columns
+            auto sizer_filaments0 = this->p->sizer_filaments->GetItem((size_t) 0)->GetSizer();
+            auto sizer_filaments1 = this->p->sizer_filaments->GetItem(1)->GetSizer();
+            if (p->combos_filament.size() < 2) {
+                sizer_filaments1->Clear();
+            } else {
+                size_t c0 = sizer_filaments0->GetChildren().GetCount();
+                size_t c1 = sizer_filaments1->GetChildren().GetCount();
+                if (c0 < c1)
+                    sizer_filaments1->Remove(c1 - 1);
+                else if (c0 > c1)
+                    sizer_filaments1->AddStretchSpacer(1);
+            }
         }
-    }
 
-    show_SEMM_buttons(); // ORCA
+        show_SEMM_buttons(); // ORCA
 
-    for (size_t idx = filament_id ; idx < p->combos_filament.size(); ++idx) {
-        p->combos_filament[idx]->update();
+        for (size_t idx = filament_id ; idx < p->combos_filament.size(); ++idx) {
+            p->combos_filament[idx]->update();
+        }
     }
 
     update_filaments_area_height(); // ORCA
@@ -5368,15 +5369,22 @@ void Sidebar::delete_filament(size_t filament_id, int replace_filament_id) {
         filament_id = filament_count;
     }
 
-    if (filament_id > filament_count)
+    // Mixed (virtual) slots have no combo of their own, so their config index lies past
+    // filament_count; bound explicit ids by the total slot count instead.
+    size_t total_filaments = wxGetApp().preset_bundle->filament_presets.size();
+    if (filament_id > filament_count && filament_id >= total_filaments)
         return;
 
-    if (wxGetApp().preset_bundle->is_the_only_edited_filament(filament_id) || (filament_id == 0)) {
-        wxGetApp().get_tab(Preset::TYPE_FILAMENT)->select_preset(wxGetApp().preset_bundle->filament_presets[0], false, "", true);
-    }
+    bool is_mixed = (filament_id >= p->combos_filament.size());
 
-    if (p->editing_filament == filament_id || p->editing_filament >= filament_count) {
-        p->editing_filament = -1;
+    if (!is_mixed) {
+        if (wxGetApp().preset_bundle->is_the_only_edited_filament(filament_id) || (filament_id == 0)) {
+            wxGetApp().get_tab(Preset::TYPE_FILAMENT)->select_preset(wxGetApp().preset_bundle->filament_presets[0], false, "", true);
+        }
+
+        if (p->editing_filament == filament_id || p->editing_filament >= filament_count) {
+            p->editing_filament = -1;
+        }
     }
 
     // update_num_filaments() shrinks filament_is_mixed along with the other per-filament arrays,
@@ -5387,8 +5395,12 @@ void Sidebar::delete_filament(size_t filament_id, int replace_filament_id) {
         is_mixed_snapshot = opt->values;
 
     wxGetApp().preset_bundle->update_num_filaments(filament_id);
-    wxGetApp().plater()->get_partplate_list().on_filament_deleted(filament_count, filament_id);
-    wxGetApp().plater()->on_filaments_delete(filament_count, filament_id, replace_filament_id > (int)filament_id ? (replace_filament_id - 1) : replace_filament_id, is_mixed_snapshot);
+
+    // filament_count only counts physical combos, so with mixed slots present it is not the
+    // new number of slots; recompute from the shrunk preset list for the downstream updates.
+    size_t total_after_delete = wxGetApp().preset_bundle->filament_presets.size();
+    wxGetApp().plater()->get_partplate_list().on_filament_deleted(total_after_delete, filament_id);
+    wxGetApp().plater()->on_filaments_delete(total_after_delete, filament_id, replace_filament_id > (int)filament_id ? (replace_filament_id - 1) : replace_filament_id, is_mixed_snapshot);
     wxGetApp().get_tab(Preset::TYPE_PRINT)->update();
     wxGetApp().preset_bundle->export_selections(*wxGetApp().app_config);
 
@@ -19495,8 +19507,10 @@ void Plater::on_filaments_delete(size_t num_filaments, size_t filament_id, int r
         }
     }
 
-    // update UI
-    sidebar().on_filaments_delete(filament_id);
+    // update object/volume/support(object and volume) filament id
+    // Must run before UI update which triggers update_mixed_filament_list() →
+    // update_objects_list_filament_column() that clips extruders above total count.
+    sidebar().obj_list()->update_objects_list_filament_column_when_delete_filament(filament_id, num_filaments, replace_filament_id);
 
     // update global support filament
     static const char *keys[] = {"support_filament", "support_interface_filament"};
@@ -19510,8 +19524,8 @@ void Plater::on_filaments_delete(size_t num_filaments, size_t filament_id, int r
             }
         }
 
-    // update object/volume/support(object and volume) filament id
-    sidebar().obj_list()->update_objects_list_filament_column_when_delete_filament(filament_id, num_filaments, replace_filament_id);
+    // update UI — runs after remap so update_mixed_filament_list() won't clip remapped extruder IDs
+    sidebar().on_filaments_delete(filament_id);
 
     // update customize gcode
     for (auto item = p->model.plates_custom_gcodes.begin(); item != p->model.plates_custom_gcodes.end(); ++item) {